Term: caudal fin ventral side
Name: caudal fin
Synonyms: tail, tail fin
Definition: Fin that is the most posterior median fin. It is composed of a complex of three modified centra and modified neural and hemal arches and spines.
Ontology: Anatomy Ontology [ZFA:0001058]

Name: ventral side
Synonyms: ventral
Definition: An anatomical region that is the entire part of an anatomical structure ventral to a horizontal plane and bounded on one side by the same horizontal plane.
Ontology: Spatial Ontology [BSPO:0000068]